Value Of Low-dose CT Perfusion In Preoperative Evaluation Of Differentiation Degree And Prediction Of EGFR Mutation In Gastric Cancer

Part Ⅰ Value of Low-dose CT Perfusion Parameters in Preoperative Evaluation of Differentiation Degree of Gastric CancerObjective:To evaluate the degree of differentiation of gastric cancer preoperatively by low-dose CT perfusion imaging and the correlation between different clinicopathological factors and the degree of differentiation of gastric cancer.Methods:Eighty-three patients with gastric cancer confirmed by gastroscopy were scanned with low-dose perfusion with 320-slice multi-slice spiral CT.Four perfusion parameters,blood flow(BF),blood volume(BV),permeability surface(PS)and mean transit time(MTT)were measured.The area-under-the-curve(AUC)was analyzed by receiver operating characteristic(ROC)of CT perfusion parameters.According to the postoperative pathological results,the perfusion parameters of different groups were compared.The correlation between gender,age,lesion size and location,T stage,lymph node metastasis and different tumor indexes and the degree of differentiation of gastric cancer was analyzed.Results:Compared with the poorly differentiated gastric cancer group,the BF,BV and PS values in the middle and high differentiation group were significantly decreased(P<0.05).The MTT value of the middle and high differentiation group was lower than that of the low differentiation group,and no statistical difference was found(P>0.05).The AUC of BF was 0.668(sensitivity was 77.8%;The specificity was 62.5%),and the AUC of BV was 0.728(sensitivity was 66.7%;The specificity was 70.8%),and the AUC of PS was 0.781(sensitivity was 81.5%;Specificity of 70.8%).Gender,age,location of gastric cancer,T stage,lymph node metastasis were correlated with the degree of differentiation of gastric cancer(P<0.05).There was no correlation between lesion size,CEA,CA199,AFP and differentiation degree of gastric cancer(P>0.05).Conclusion:The perfusion parameters BF,BV and PS have certain significance for preoperative evaluation of the differentiation degree of gastric cancer,and can be used as auxiliary observation indexes.Part Ⅱ Value of Low-dose CT Perfusion in Predicting EGFR Mutations in Gastric CancerObjective:To investigate the correlation between epidermal growth factor receptor(EGFR)mutation and gastric CT perfusion parameters in patients with gastric cancer.Methods:In selected patients with gastric cancer confirmed by gastroscope,a low dose 320 row multislice CT perfusion scanning.Four perfusion parameters:blood flow(BF),blood volume(BV),permeability surface(PS)and mean passage time(MTT)were measured.A total of 69 patients with postoperative immunohistochemical results,according to the results of genetic testing in EGFR mutation positive groups and EGFR mutation negative groups,to compare different EGFR mutation perfusion parameters differences between groups,the difference was statistically significant parameters make judgment diagnostic performance the receiver-operating characteristic curve.Results:The BV and PS values of positive EGFR mutation were higher than those of negative EGFR mutation group,and there were statistically significant differences between groups(P<0.05).The area under the curve corresponding to BV and PS was about 0.778and 0.705,andits sensitivity and specificity were 90.9%、70.8%and81.8%、55.2%.When BV is greater than 13.3 mL/100g or PS is greater than 18.77 mL/100g/min,it suggested the possibility of positive EGFR mutation.andConclusion:CT perfusion parameters of gastric cancer can help to predict EGFR gene mutation,make up for the absence of EGFR detection to a certain extent,and have certain reference value for clinical diagnosis and treatment.